The document U.S. Pat. No. 6,135,654 discloses an ink jet printing machine. An object to be printed is placed on a belt conveyor in order to be presented successively to a pretreatment device, an ink jet printing device and a drying device.
However, an ink jet printing apparatus requires a very high degree of precision in the relative positioning between the surface of the object to be printed and the ink ejection nozzles. This precision is of the order of several microns (μm). However, the use of a belt conveyor does not provide the means to achieve a such precision.